A broadcast network of the related art generally uses a Moving Picture Experts Group-2 Transport Stream (MPEG-2 TS) for transmission of multimedia contents. That is, the MPEG-2 TS is used as a representative transmission technique for transmitting a bitstream in which a plurality of broadcast programs (a number of encoded video bit streams) are multiplexed in a homogeneous transmission environment. For example, the MPEG-2 TS is suitable for use in digital TV broadcasting of the multimedia era.
FIG. 1 illustrates a hierarchical structure for supporting the MPEG-2 TS according to the related art.
Referring to FIG. 1, to support the MPEG-2 TS, there are a media coding layer (MEDIA CODING LAYER) 110, a synchronization layer (SYNC LAYER) 120, a delivery layer (DELIVERY LAYER) 130, a network layer (NETWORK LAYER) 140, data link layer (DATA LINK LAYER) 150, and a physical layer (PHYSICAL LAYER) 160.
The media coding layer (MEDIA CODING LAYER) 110 and the synchronization layer (SYNC LAYER) 120 are constructed in a format that facilitates use of media data as the basic unit of recording or transmission. The delivery layer (DELIVERY LAYER) 130, the network layer (NETWORK LAYER) 140, the data link layer (DATA LINK LAYER) 150, and the physical layer (PHYSICAL LAYER) 160 construct a multimedia frame for recording of a data block (for example, ‘AU’) in a format constructed by the synchronization layer (SYNC LAYER) 120 in a separate recording medium or for transmission of the data block. The constructed multimedia frame is transmitted to a subscriber terminal through a predetermined network.
To this end, the synchronization layer (SYNC LAYER) 120 is constructed by a fragmentation block (FRAGMENT BLOCK) 122 and an access unit (ACCESS UNIT) 124, and the delivery layer (DELIVERY LAYER) 130 is constructed by an MPEG-2 TS/MP4 132, an RTP/HTTP 134, and an UDP/TCP 136.
However, the MPEG-2 TS has several limitations in supporting multimedia services. For Example, the MPEG-2 TS only supports one-way communication. Moreover, transmission inefficiencies due to a fixed frame size, a transmission protocol specialized for audio/video, and unnecessary overhead in transmission using Internet Protocols (IPs) occur.
To address the limitations of the MPEG-2 TS, the MPEG MEDIA Transport (MMT) standard is newly suggested as a multimedia transmission technique for supporting multimedia services based on the MPEG technology. In particular, the MMT standard has been proposed by the MPEG to overcome the limitations of the MPEG-2TS.
Moreover, the MMT standard aims at defining a more friendly transmission technique for the IP that is a basic technique in a transmission network for the multimedia services. Hence, the MMT standard may be applied to efficiently transmit hybrid contents via a heterogeneous network.
The term hybrid contents refers to a set of contents in which multimedia elements corresponding to video/audio/application exist together, i.e., hybrid multimedia. The application includes an application that supports an additional service such as a widget service that may be additionally provided in a situation where a screen corresponding to particular content is provided in user equipment.
The heterogeneous network refers to a network where a broadcast network and a communication network coexist. The hybrid network may be a representative example of the heterogeneous network. For example, the hybrid network collectively refers to at least one broadcast network and at least one IP network which are used together for a hybrid multimedia service.
Considering the foregoing points, to support a hybrid multimedia service that provides an application associated with a real-time broadcast service composed of audio/video in a broadcast system, it may be desirable for the MMT standard to provide a definition of control information for associating a particular application with a real-time broadcast service and an application service by using the definition.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.